Nahjul Balagha Letter 38

To the people of Egypt when he appointed (Malik) al-Ashtar as
their Governor.

From the slave of Allah, Ali, Ameerul Momineen to the people who became wrathful for the sake of Allah when He was disobeyed on His earth and His rights were ignored and oppression had spread its coverings over the virtuous as well as the vicious, on the local as well as the foreigner. Consequently, no good was acted upon nor any evil was avoided.

Now, I have sent to you a man from among the servants of Allah who allows himself no sleep in days of danger, nor does he shrink from the enemy at critical moments. He is severer on the wicked than a blazing fire. He is Malik bin Harith, of (the tribe) Muzhij. Therefore, listen to him and obey his orders that accord with right, because he is one of the swords of Allah, whose edge is not dull and which does not miss its victim. If he orders you to advance, advance, and if he orders you to stay, stay, because he surely neither advances or attacks nor puts anyone backward or forward save with my command. I have preferred him for you rather than for myself because of his being your well-wisher and the severity his harshness over your enemies.